BONE HISTOMORPHOMETRY USING INTERACTIVE IMAGE-ANALYSIS - A METHODOLOGICAL STUDY WITH APPLICATION ON THE HUMAN TEMPOROMANDIBULAR-JOINT

The aim was to develop a reproducible method for bone histomorphometry with the aid of a computerized image analysis program, and to examine the variation when assessing the total and the trabecular bone volume . Histologic sections of 18 temporomandibular joint autopsy specimens were read interactively using a cursor. The two parameters total bone volume and trabecular bone volume, of the condyle and the temporal com ponent respectively, were estimated 2 x by 1 observer using 3 differen t threshold settings: an automatic, a semi-automatic and a manual tech nique. The threshold was based on the gray-scale distribution of the i mage. 2 observers read the same sections with the aid of the semi-auto matic technique. The intraobserver variation expressed as coefficient of variation ranged between 1.9% and 7.1% for the different parameters , when the automatic threshold setting technique was employed, and bet ween 2.8% and 8.7% with the semi-automatic technique. The manual techn ique resulted in a high intra-observer variation with a coefficient of variation between 5.2% and 19.9%. There was a systematic difference b etween the estimates of the 2 observers. In general, intra- and inter- observer variation was higher in the temporal component than in the co ndyle. The inter-section variation was moderate, the coefficient of va riation ranging from 3.8% to 11.1%. The automatic and semi-automatic t echniques resulted in comparable intra-observer variation, with a lowe r bias in the estimates of the semi-automatic technique. By letting on e observer apply the semi-automatic technique, it was possible to achi eve fast and reproducible analysis of the total and trabecular bone vo lume.